Bus controller and bus control system

A bus control system comprising:

• a unit connected to a high-speed serial bus for performing high-speed transmissions;
• a unit connected to a low-speed serial bus for performing low-speed transmissions;
• a memory for storing addresses of said units and predetermined transmission data to be transmitted to said units;
• a transmission interface for transmitting a transmission frame formed by reading said predetermined transmission data from said memory;
• a transmission address comparator for comparing the addresses of said destination units to output a signal indicating whether said frame is to be transmitted using said high-speed serial bus or said low-speed serial bus;
• and a transmission change-over switch for responding to said signal and selecting either said high-speed serial bus or said low-speed serial bus to output said transmission frame.

A bus control system comprising:

• a unit connected to a high-speed serial bus for performing high-speed transmissions;
• a unit connected to a low-speed serial bus for performing low-speed transmissions;
• a memory for storing addresses of said units and predetermined transmission data to be transmitted to a plurality of destination units;
• a serial bus transmission controller for performing a speed switching between a high-speed transmission and a low-speed transmission in accordance with the addresses said destination units;
• a transmission interface for transmitting a transmission frame formed by reading said predetermined transmission data from said memory to said high-speed serial bus at a transmission speed set by said speed switching;
• and a low-speed serial bus controller provided between said high-speed serial bus and said low-speed serial bus for transmitting said transmission frame to said low-speed serial bus when the transmission speed of said transmission frame transmitted from said high-speed serial bus is low.